3.15.3 Cumulative Environmental Effects Related to Air Quality

As noted in Table 3.2-1, the geographic scope for air is quality during construction is lands within 0.25 mile of active construction. Air emissions during construction would be limited to vehicle and construction equipment emissions and dust and would be localized to the Project’s active construction work areas and areas adjacent to these active work areas. A range of approximately 0.25 mile conservatively captures the distance these emissions would travel before becoming negligible and unlikely to contribute to a cumulative impact. As the Project stores and generates power without generating carbon emissions, longterm operational effects on air quality would be negligible, and are not included in the cumulative effects analysis.

As detailed in Table 3.2-2, there are two projects that occur within the geographic scope for air quality during construction: 1) Gateway West Transmission Line Project, and 2) Gateway South Transmission Line Project. These projects tie into the existing Aeolus Substation, which represents less than 7 percent (approximately 462 acres) of the Project’s Footprint of Potential Disturbance and the only physical proximity between the Project and others within the geographic scope for potential effects on air quality.

Issues Identified for Analysis

Air pollutant emissions would occur primarily during construction. Air pollutants may include construction sources such as traffic, construction equipment, and fugitive dust from earth moving. These emissions would combine with emissions from other existing local and regional sources of air pollutant to affect ambient concentrations of pollutants.

Results

Construction of the Project would temporarily increase emissions of some criteria pollutants, GHGs, and hazardous/toxic air pollutants surrounding the construction workspaces. This is due to emissions from the combustion engines used to power construction equipment, vehicle traveling to and from construction sites, and fugitive dust resulting from equipment movement on dirt roads and earth-disturbing activities. Construction emissions would cease with the end of construction; thus, the period of influence for cumulative air quality impacts during construction of the Project and other projects would be temporary. The Project, and other projects, would implement mitigation measures to minimize construction impacts on air quality such as applying water or dust control chemicals to minimize fugitive dust (BLM 2013, 2022b). Construction emissions would also disperse within the airshed and diminish in concentration with distance from active work areas. Since the Gateway West Transmission Line Project has completed construction (within the geographic scope) and Gateway South Transmission Line Project is undergoing construction and is expected to be completed prior to Project construction, cumulative air quality impacts would be negligible since there would be no construction overlap.